Im running 31 inch all terrains and max psi is 50. I have them at 35 psi and was wondering if that was too high. I dont want them to wear down in the middle.

Love
Trash

at my dealership, we put all tires at 35. thats what toyota recomends. i dont know about after market tire manufacturers, but thats what we do at least.

Depends on the vehicle and weight carried. My 2001 Double Cab 4x4 has a factory recommendation for 26 psi front and rear, from curb weight all the way to max load.

Another rule of thumb is that tires should run about 4-5 psi higher when they are hot (after driving at least 10 miles at speed) than when cold. Much more than a 4-5 psi jump usually means the sidewalls are flexing too much, creating excess heat in the tire (thus the excessive jump in air pressure). Nitrogen filled tires won't change as much with temperature, so this "old wives tale" probably won't work very well for tires filled with N2.

BFG All Terrains are famous for wearing out the edges of the tread (soft sidewalls for increased traction off-road), so if you run them on the street a lot, I'd put at least 30-32 psi in. Of course, more psi means a harsher ride, so pick your poison.

i read that tire pressure raises 1 psi for every 10 degree raise in air/road temp.

best way to figure out optimum tire pressure is by testing w/ some chalk though b/c it depends on the tire/rim combo and weight of the vehicle.

find a flat parking lot. draw a chaulk line across your tire, move the truck about fifty feet in a straight line, when the chaulk wears off even that the perfecr tire pressure.

I have a collection of techniques to determine proper inflation pressure on the web page below, some have been mentioned above:
http://www.4crawler.com/Diesel/Tires.shtml#ProperInflation

I run my 33x10.50s anywhere from 20psi to 50psi on the road. Usually around 35 psi for most things, I'll bump up to 40-50 for long highway trips or when heavily loaded and 30 and lower if I am doing gravel roads or need some extra traction.

The 35 psi in every tire on every vehicle is a "good enough approach." <img src="/forums/images/graemlins/wink.gif" alt="" /> Your door jam tag will tell you what pressure to set your tires with factory sized tires, wheels, and weight. 4crawler has some great info. <img src="/forums/images/graemlins/kewl.gif" alt="" />

I used masking tape across the tire to get quick feedback on tire wear pattern.. After about 15 miles you can see exactly what the wear pattern is across the tread.. for my Bridgestone Dueler AT 31's I ended up with 36psi front 34 rear.

4Crawler has done the same thing using chalk marks I believe..

I close to 800lbs heavier than stock with all added iron underneath..

I use the big sidewalk chalk and run a few passes across the width of the tread. Then drive it about a hundred yards on pavement forward then reverse without turning. You will see where it wears down and can adjust the pressure as needed.

I run 30 front, 32 rear in the 4Runner, depending on conditions. This si my baseline pressure.

I bump to 38 front and 40 rear on road trips, and waaaay down on trails.